1. Field of the Invention
The present invention pertains to a device for targeting a satellite dish antenna at a satellite, and, more particularly, to an apparatus which allows a user to adjust the orientation of the satellite dish antenna mounted on a vehicle while viewing the elevation of the satellite dish antenna that has been compensated for by a parabolic offset angle and any inclination angle of the vehicle.
2. Statement of the Problem
Satellite antenna systems have become an increasingly popular method to receive television programming signals. Digital programming is now delivered by several companies using satellites to transmit signals to earth-based satellite dishes. These antenna systems are typically installed on fixed surfaces, such as on buildings or homes. Some consumers install small satellite dish antennas on recreational vehicles (RVs). When the antenna system is mounted on an RV, the vehicle must either be leveled before using the satellite antenna system or any inclination must be manually compensated for before targeting the antenna dish at the satellite.
Before the satellite dish antenna is targeted at the satellite, the user must know the target elevation required to receive a signal from a satellite at the location of the satellite dish antenna. Conventionally, the target elevation is obtained by inputting the local zip code of the location of the satellite dish antenna, into a satellite receiver system. The user then adjusts the orientation of the satellite dish antenna first by adjusting the azimuth to a predetermined setting, and then the elevation until the elevation of the satellite dish antenna corresponds to the target elevation obtained from the receiver.
Conventional systems, whether stationary or mobile, require the user to provide a level surface for the antenna system to accurately target the elevation of the satellite dish antenna. Absent a level surface, the user is required to compensate for the incline to target the satellite dish antenna to receive the signal from the satellite at a particular location.
Conventional systems with an offset antenna feed further require the user to compensate for a parabolic offset angle associated with the antenna dish. An antenna feed inevitably creates a shadow between the signal and the satellite dish antenna where the signal cannot reach. On large dishes, this shadow is inconsequential. However, as a result of the popularity of mobile satellite antenna systems, antenna dishes have become increasingly smaller. Thus, reception by smaller antenna dishes begins to suffer as the shadow cast on the satellite dish by the antenna feed grows proportionally larger with respect to the decreasing size of the satellite dish. To provide better reception, designers offset the antenna feed with respect to the center of the dish. Because the signal is reflected to a feed at the center of the conventional dish, the dish with an offset feed must be adjusted to reflect the incoming signal to the offset feed. This adjustment is expressed as an angle, measured between the face of a normal parabolic antenna dish targeted to receive a signal (or measured between a plane perpendicular to the incoming signal) and the face of an antenna dish with an offset antenna feed set to reflect the incoming signal to the offset antenna feed. This angle is known as the parabolic offset angle and is typically provided by the manufacturer in the specifications for the antenna system.
Conventional systems require the user to manually compensate for the parabolic offset angle. For example, the user orients the antenna dish so that the elevation of the antenna dish corresponds to the target elevation, and then adjusts the dish elevation to compensate for by the parabolic offset angle. Other conventional systems provide the elevation in degrees, compensated for the parabolic offset angle, stamped into a mechanical inclinometer, thus allowing the user to view the corresponding dish elevation as it is elevated. However, such conventional systems do not allow the user to remotely view the dish elevation.
For example, assume the parabolic offset angle is "twenty-four" degrees, and the target angle for a desired satellite is "forty-five" degrees for a given location. Furthermore, assume the satellite dish antenna is level so that there is no inclination angle. The user of a conventional system orients the satellite dish antenna to an elevation of "forty-five" degrees and then corrects the dish elevation "twentyfour" degrees to compensate for the offset angle. Alternatively, the user views the target angle corrected for the offset angle stamped into the mechanical inclinometer. However, the user is required to be within viewing distance of the stamped elevation markings.
An additional calculation is now required if the satellite dish antenna is not on a level surface. The user now has to compensate for the incline when calculating the corrected target elevation. However, unlike the target angle which is readily obtained from the satellite receiver, and the parabolic offset angle which is typically provided with the antenna system specifications, the user must separately measure or otherwise estimate the incline of the antenna dish. While some conventional systems provide a mechanical inclinometer which swings from the elevating tube to provide an approximate inclination, these systems require the user to view the elevation at the dish and do not provide the user with a remote display.
Conventional satellite dish antennas require additional time and are prone to user inaccuracies. Therefore, a need exists to provide the user of satellite antenna systems with a device that allows the user to accurately and easily target the satellite antenna dish to receive a satellite signal, without being leveled before use. A further need exists to provide the user with an accurate and easy to use device which will automatically compensate for the parabolic offset angle.
A need also exists to provide the user with a device which will automatically shut off to conserve battery power. A further need exists for a display that can be remotely viewed, including a display that can be mounted in close proximity to the satellite antenna dish controls.
A patentability search on the present invention was conducted and the results of this search are:
U.S. Pat. No. 4,707,699 utilizes an inclinometer attached to the antenna mount which is remotely sensed. Elevation control software controls the elevation drive motor. The control system automatically positions a portable parabolic fish antenna carried on the roof of a well logging truck. At a particular site, the earth's latitude and longitude is entered into the portable truck computer, the portable parabolic antenna is adjusted by the computer to a predetermined elevation (the base of the parabolic antenna has been reasonably leveled) and then, while keeping the elevation constant, the azimuth angle is swept slowly under computer control. When the satellite signal is detected, the satellite is locked in.
U.S. Pat. No. 5,227,806 pertains to a stabilized ship antenna system for satellite communication utilizing an inclination angle detector mounted on the AZ frame to detect an inclination angle. The elevation of the antenna is controlled by successive addition of the detected inclination angle to the control algorithm.
U.S. Pat. No. 5,077,561 sets forth a computerized antenna mount system for continuously tracking a satellite in geosynchronous orbit that has an inclined orbit with respect to the equator. The antenna mount automatically adjusts the declination angle of the ground station satellite antenna as a function of time after iteratively compiling the declination angle history from one complete orbit of a satellite. The adjustment is made by peaking the satellite signal received from the satellite turning.
None of the above patents provide a solution to the above stated needs.